1. Technical Field
The present invention relates to a polarizing element, a liquid crystal device, and an electronic apparatus.
2. Related Art
As one type of polarizing element, polarizing glass is known. Since the polarizing glass can be configured by using only inorganic materials, compared to a polarizing plate containing organic materials, the degradation with respect to light is markedly low. Thus, the polarizing glass has attracted attention in recent years as an optical device that is useful for a liquid crystal projector in which luminance increases are progressing.
As general polarizing glass, polarizing glass disclosed in JP-A-56-169140 is known. A method of manufacturing the polarizing glass is as follows.
(1) A glass product having a desired shape is produced from a composition that contains at least one halide selected from the group consisting of a chloride, a bromide, and an iodide and silver.
(2) The glass product is heated up to a temperature that is higher than the strain point but is not higher than the softening point of the glass by about 50° C. over a period that is sufficient for generating crystals of AgCl, AgBr, or AgI in the glass product, whereby a crystal containing product is produced.
(3) The crystal containing product is stretched under stress at a temperature that is higher than the annealing point but is lower than a temperature at which the glass presents a viscosity of about 108 poises such that the crystal stretches at the aspect ratio of at least 5:1.
(4) The product is exposed to a reducing atmosphere at a temperature that is higher than about 250° C. but is not higher than the annealing point of the glass by about 25° C. over a period that is sufficient for developing a chemical reducing surface layer on the product. Here, at least some of the stretched halide silver particles are reduced to silver elements.
In addition, in JP-A-2004-256915, particles that have an absorption peak in the visible region and have a particle diameter of about several nm to several tens of mm, that is, so-called nanoparticles are disclosed. More specifically, gold particles having an extremely high absorption wavelength of 530 nm and silver particles having an extremely high absorption wavelength of 420 nm are disclosed.
In the manufacturing method disclosed in JP-A-56-169140, halides uniformly educe in the glass product, but only halides located on the surface layer of the glass product are reduced in reducing process. Accordingly, halides remain in the center portion of the glass product in the thickness direction. As a result, the transmittance of the polarizing element decreases, and, in a case where the polarizing element is used in a liquid crystal display device or the like, there is concern that a sufficient brightness level cannot be acquired.
In addition, many of general liquid crystal display devices for full-color display, for example, include color filters configured by coloring material layers of a plurality of types of red (R), green (G), and blue (B). Generally, the polarizing characteristics of a polarizing element have wavelength dependence, and, in a case where one polarizing element is used, the polarizing characteristics for red light, green light and blue light are different from each other. Accordingly, it is common to use a polarizing element that has an average polarizing characteristic for red light, green light, and blue light. In other words, the polarizing characteristics of the polarizing element are not optimized to any one of red light, green light, and blue light. As a result, there is a problem that a brightness level, contrast, and color reproducibility that are sufficient for a liquid crystal display device cannot be acquired.
In addition, in JP-A-2004-256915, nanoparticles having an absorption wavelength peak in a visible region are described to be used in a coating material, and the application of the nanoparticles to a polarizing element is not suggested.